The study by the comptroller’s offices of research and education accountability says such taxes have stagnated and are not expected to be sufficient to maintain existing infrastructure and meet long-term transportation needs.

Tennessee relies heavily on fuel taxes to fund its highways and does not use debt financing, tolls or general fund revenues. The report suggests those as possible revenue options, as well as motor fuel tax rates.

The state’s 21.4-cents-per-gallon gas tax hasn’t been raised since 1989, and the state is struggling to meet its road building and maintenance needs.

Gov. Bill Haslam has acknowledged that the state’s transportation funding is a challenge and is considering legislation to overhaul the state’s gas tax.